Spotting at 13 weeks but baby Ok

Megan • Trying for our third! First baby a miscarriage, chemical then rainbow. Second baby 9 months of trying 4 with clomid. Hoping for a quick easy pregnancy for #3
I went to the ER for some light spotting yesterday since I was out of town and couldn't get to the OB. After two miscarriages this terrified me. I got an ultrasound and heartbeat was 163 baby was moving all around. They found no cause for the bleeding. Maybe just that I did a lot of walking the day before. Has anyone has similar stories with positive outcomes? I just need some more reassurance! Thanks!!